Certified Professional Horticulturist (CPH) Practice Exam

Which element is the principal component in cell wall development?

1. Calcium

2. Potassium

3. Hydrogen

4. Phosphorus

The correct answer is: Calcium

The principal component in cell wall development is calcium. Calcium plays a vital role in the formation and stability of plant cell walls by contributing to the structure of pectin, which is a key component of the middle lamella that cements cells together. It also helps in maintaining the structural integrity and rigidity of cell walls, facilitating cell expansion and growth. The presence of calcium is essential for the normal functioning of cell membranes and the signaling processes that govern various physiological functions within the plant. Calcium’s role in cell wall development is distinctly different from that of the other elements listed. Potassium, while crucial for many physiological processes such as enzyme activation and osmoregulation, does not directly contribute to cell wall structure. Hydrogen is integral to various cellular processes, including maintaining pH balance and participating in biochemical reactions, but again, it does not have a direct role in cell wall construction. Phosphorus is important for energy transfer and nucleic acid synthesis but is not a structural component of cell walls. Thus, calcium is the correct choice as the principal element associated with cell wall development.